102 "COEFFICIENT OF DIFFUSION OF CELLS" 



some of the stain down with it, vitiating the results, 

 for it has been shown that agar is not very soluble 

 in cold stain. 1 



As regards Examination: The observation of cells 

 floating near a bubble under the cover-glass should 

 be avoided. The fact that blood-cells in such a 

 situation will stain before others has already been 

 noted. 1 I consider this to be due to these cells floating 

 in a small quantity of alkaline citrated plasma collected 

 round the bubble. 



Consequently the experiments have all been made 

 within the compass of the above restrictions. It may 

 also be advised that when unnucleated cells contain 

 granules in their cytoplasm the staining of the gran- 

 ules gives a more constant rate than the staining of the 

 cytoplasm. By this means it is seen that the cf of the 

 blood-platelet is identical with that of the polymorpho- 

 nuclear cells. 



1 "On the Death of Leucocytes" (H. C. Ross, Journal of Physiology, 

 vol. xxxvii., p. 327, 1908). 



